LM204 - Audibility FAST: Introducing Figuring Audibility for Speech Tool

Abstract:
The traditional HL audiogram and PTA-based classifications provide standardized hearing assessment information but do not capture an individual's unique hearing loss because they assume average ear canal acoustics.  This means that the HL audiogram is often insufficient for patients and families to understand the consequences of hearing loss on speech understanding.  This presentation will review options for calculating equivalent SII values, which measure audibility for speech information.  Use of the SII for informational and motivational counseling will be presented emphasizing the pediatric populations.  A novel SII calculator and innovative applications of the tool with case examples will be discussed.

Summary:
In this session, Knowledge Implementation in Pediatric Audiology (KIPA) group members will discuss the use of audibility measurements as a counseling tool for families of children with hearing loss and discuss the options available to make audibility calculations.  Audibility is most commonly expressed using the speech intelligibility index (SII), (Hornsby, 2004).  Audibility calculations go beyond long-standing mild-moderate-severe degree descriptions.  Hearing loss degree categories do not provide sufficient information for patients and families to understand the consequences of an identified hearing loss.  For example, a child with a hearing loss that is identified as moderate in degree may experience unaided audibility as low as 0% depending on the configuration of the loss (Sapp, et al, 2023).

The need for consistent aided audibility drives many of the recommendations that audiologists make during their clinical interactions with patients and families.  Child-specific measures of ear canal acoustics obtained via the real-ear-to-coupler-difference (RECD) significantly improve the accuracy of both aided and unaided audibility calculations and allow for individualized counseling about a child's overall access to speech information.  By comparing aided audibility to normative data, audiologists can also ensure that their fittings meet the expected benefit range for children with similar levels of hearing loss (Bagatto, et al, 2023).

Audiologists have several options for calculating audibility using the results obtained from either the pure tone audiogram or a threshold ABR.  Some clinical audiometers and ABR systems may provide an estimate of SII values, but these are general estimates and do not integrate knowledge about the patient's age or ear canal acoustics into the calculation.  To obtain the most precise audibility measurements, audiologists use real-ear probe microphone verification equipment to convert thresholds into SPL and generate child-specific and ear-specific audibility calculations.  However, it may not be feasible to access probe-microphone equipment in most testing suites or ABR test environments. When real-ear measurement is not available, age-appropriate average RECD values are available (Moodie et al., 2016; McCreery et al., 2013; Watts et al., 2020)).  What is lacking is a method to efficiently convert standard audiological or ABR test results to accurate audibility calculations.

To address these clinical limitations when using audibility as a counseling tool, the KIPA team developed a mobile tool for audiologists to simulate SII calculations, the Figuring Audibility for Speech Tool (FAST).  The tool is free to use and accessible via the KIPA website (www.kipagroup.org). Audiologists input hearing thresholds and specify the patient's age to integrate the appropriate average RECD.  FAST generates both an estimated audibility value and provides the upper and lower bounds of the estimated ranges when applying average RECD values.  This learning module will emphasize the advantages of using the FAST as a novel solution for audiologists who are incorporating audibility calculations into their informational counseling and will present examples of successful and efficient integration of the tool into clinical practice.